Rock-drill



J.K. FIRTH.

(No Model.)

ROCK DRILL.

No. 596,149. Patented Dec. 28,1897.

Fries.

.IOSEPH KQFIRTH, OF SAN FRANCISCO, CALIFORNIA.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 596,149, dated December28, 1897.

I Application filed December 16, 1896- Serial No. 615,905. (No model.)

To all whom it may concern:

Be it known that I, JOSEPH K. FIRTH, a citizen of the United States,residing at San Francisco, in the county of San Francisco and State ofCalifornia, have invented certain new and useful Improvements inRock-Drills; and I do hereby declare that the following is a full,clear, and exact description thereof.

The presentinvention relates to certain new and useful improvements inrock-drills, and more especially the auxiliary-valve mechanism foroperating and controlling the main valves; and it consists in thearrangement of parts and details of construction, as will be hereinafterfully set forth in the drawings and described and pointed outin thespecification.

In the pneumatic or pressure-operated rockdrills the auxiliary valve foroperating the main valves becomes quickly worn out and rendered uselessby the movement of the drillbe obviated or overcome, thus prolonging thedurability and life of the drill mechanism and reducing the costattached to the constant repair of the auxiliary-valve mechanism.

In order to fully comprehend the invention,

- reference must be had to the accompanying tion of the arrow 2 in Fig.3.

sheet of drawings, wherein Figure l is a broken longitudinal sectionalView in side elevation, taken on line 00 00, Fig. 3, showing thepiston-casing and the mainvalve chamber, the valve of the main-valvechamber, and the port communication between said chamber and thepiston-casing, said mechanism being viewed in the direc- Fig. 2 is asimilar view taken on line y 3 Fig. 3, and viewed from the rear, or inthe direction of the arrow 1,said view showing the auxiliary-valvechamber, the location of the valve-stem and the valve therein, the portcommunication between said chamber and the main-valve chamber and thepiston-casing; and Fig. 3 is a vertical cross-sectional View taken online to ca, Fig. 2.

In the drawings the letter A is used to indicate the casing of thedir1l,within which works the piston A. This casing has secured to thetop thereof at any suitable point the mainvalve casing A which casing isformed with the steam or air chamber a and the valvechamber a, the twochambers communicating by means of the ports a and a while the chamber acommunicates with the pistonchamber of the drill-casing by means of theports I) b.

To the rear wall of the main-valve casing is formed the auxiliary-valvecasing 13, within the valve-chamber B of which works the hollow valve BThis valve is cut away between the points 1 2, so as to form an annularspace 3 between the wall of the valve and the inner wall of thevalve-casing.

Within a socket formed in the lower end of the valve B is fitted a ballB This ball works through an opening 5, formed in the drill-casing andrests upon the face of the piston A, as shown in the drawings. -Thisball being free to rotate in all directions it does not become worn inany particular place by contact with the piston. The valve is raised andlowered by the movement of the piston, for as the piston is movedforward the ball rides upon the inclined portion 6 of the said piston,so that it is graduallyraised from the level portion 8 of the pistonuntil the point 7 is reached, after which it remains upheld by thestraight portion 9 of the piston until the piston moves upon itsbackward stroke. As the piston moves upon its backward or return strokethe valve is gradually lowered. It will be observed that the ball bearsat all times on the'piston and that no additional means, such as aretaining bushing or flange in the valve-casing, isrequired to hold theball in its socket. The ball B? being seated in the semispherical socketin the valve is capable of a universal movement, and it is caused torotate freely during the forward-and-backward stroke of the piston byfrictional engagement therewith and likewise rotates with the turning ortwisting movement of the piston. Consequently it will be observed thatthe ball rotates or turns so as to present a new surface or point ofcontact with each movement of the piston, for, as is well known, thepiston of the rock-drill not onlyhas a reciprocating movcment,bntitlikewise revolves upon its stroke in order to impart a twisting movementto the drill.

Communication is established between the valve-chamber l3 and each endof the mainvalvc chamber a by means of the portways (Z d, Figs. 1 and 2,and with the steam or air chamber a by ports (Z Connection is also madebetween the valve-chamber B and the main-valve chamber a by theexhaust-port (1. Through the main-valve casin g is formed the exhaust D,which conveys the exhaust steam or air from within the main valvechamber. \Vithin this chamber are located the main valves D I),connected by the ball D These valves, being connected, may be called areciprocating, main, or slide valve, which control the inlet ports a a,leading from the chamber a, and the outlet-ports I) I), leading to thepiston-chamber. The airor steam flowing through these ports enters thepiston-chamber back of the enlarged head E and in advance of theshoulder or collar E, respectively, of the piston.

Above the head t of the hollow valve is formed a series ofoutlet-openings e, which permit the steam or air flowing therethrongh toescape into the port (1 as the valve is raised. This valve is maintaineddownward, so as to maintain the ball against the piston A by means ofthe spring E The air or steam enters the chamber a by the pipe F, whichleads from any suitable source of supply.

As the ball 13 is raised and lowered the ports (1 and (Z, respectively,are opened and closed, so as to control the supply of air or steam tothe main-valve chamber to operate the valve located therein.

The working of the valve mechanism being well known and well understoodby those familiar with this line of machinery a detailed descriptionthereof in this application is not deemed necessary.

Having thus described my invention, What I claim as new, and desire tosecure protection in by Letters Patent, is-

1. In a rock-drill, the combination with the piston-chamber, piston, andmain valve, of a spring-pressed auxiliary valve, a ball at the endthereof projecting into the piston-chamber and engaging and supportedsolely by the piston.

2. In a rock-drill, the combination with the piston providedintermediate its ends with a reduced portion, springpressed auxiliaryvalve operated by said piston, a ball in engagement with said valve, andsaid reduced portion, and adapted to be rotated by the movement of thepiston.

In testimony whereof I affix my signature, in presence of two witnesses,this 10th day of December, 1806.

JOSEPH K. FIRTH.

lVitnesses:

N. A. ACKER, Lian 1). 01mm.

